﻿45 
  

  

  THE 
  KESPIRATOKY 
  SYSTEM 
  OF 
  MONOPHLEBUS 
  STEBBINGI, 
  VAR. 
  

  

  OCTOCAUDATA. 
  

  

  By 
  Robt. 
  E. 
  Savage. 
  

  

  (Plates 
  V-IX.) 
  

  

  Monophlebus 
  stebbingi, 
  Green, 
  var. 
  octocaudata, 
  Green, 
  is 
  a 
  large 
  Coccid 
  belonging 
  

   to 
  the 
  sub-family 
  Monophlebinae. 
  It 
  is 
  found 
  on 
  Mango, 
  Jack 
  Fruit, 
  and 
  species 
  

   of 
  Ficus, 
  in 
  India, 
  but 
  having, 
  for 
  a 
  Coccid, 
  a 
  long 
  life-history 
  — 
  being 
  but 
  single- 
  

   brooded 
  — 
  it 
  is 
  rarely 
  a 
  pest. 
  Climatic 
  conditions 
  govern 
  the 
  production 
  of 
  large 
  

   numbers 
  of 
  individuals, 
  so 
  that 
  outbreaks 
  are 
  irregular, 
  occurring 
  at 
  intervals 
  of 
  a 
  

   few 
  years. 
  

  

  Its 
  gigantic 
  proportions, 
  compared 
  with 
  other 
  Coccids 
  — 
  the 
  fully-ripe 
  female 
  often 
  

   reaching 
  a 
  length 
  of 
  2 
  cm. 
  — 
  led 
  Professor 
  Lefroy 
  to 
  suspect 
  that 
  the 
  tracheal 
  system 
  

   might 
  differ 
  from 
  the 
  usual 
  arrangement 
  found 
  in 
  Coccids, 
  and 
  upon 
  investigation, 
  

   this 
  was 
  found 
  to 
  be 
  the 
  case. 
  

  

  In 
  all 
  other 
  Coccids, 
  with 
  two 
  exceptions 
  mentioned 
  by 
  Newstead,* 
  there 
  are 
  but 
  

   two 
  pairs 
  of 
  spiracles 
  — 
  the 
  mesothoracic 
  and 
  metathoracic, 
  situated 
  ventrally 
  just 
  

   posterior 
  to 
  the 
  junction 
  of 
  the 
  pro- 
  and 
  meso-sternum 
  and 
  the 
  meso- 
  and 
  meta- 
  

   sternum 
  respectively. 
  The 
  two 
  exceptions 
  are 
  Stigmacoccus, 
  Hempel, 
  and 
  Peris- 
  

   sopneumon, 
  Newstead 
  ; 
  the 
  former 
  has, 
  in 
  addition 
  to 
  the 
  thoracic, 
  eight 
  pairs 
  of 
  

   dorsal 
  abdominal 
  spiracles, 
  while 
  the 
  latter 
  has 
  seven 
  pairs. 
  In 
  the 
  species 
  under 
  

   consideration 
  there 
  is 
  also 
  this 
  supplementary 
  dorsal 
  series, 
  seven 
  pairs 
  being 
  present. 
  

  

  1. 
  The 
  General 
  Arrangement 
  of 
  the 
  Tracheal 
  System. 
  

  

  This 
  is 
  shown 
  in 
  the 
  figure 
  on 
  Plate 
  V. 
  Only 
  the 
  main 
  trunks 
  and 
  branches 
  are 
  

   indicated, 
  as 
  the 
  minor 
  branches 
  with 
  their 
  ramifications 
  amongst 
  the 
  internal 
  organs 
  

   form 
  a 
  very 
  complex 
  system, 
  and 
  it 
  would 
  serve 
  no 
  useful 
  purpose 
  to 
  try 
  to 
  represent 
  

   them. 
  

  

  Each 
  mesothoracic 
  spiracle 
  leads 
  into 
  a 
  short 
  wide 
  trunk, 
  which 
  immediately 
  branches 
  ; 
  

   one 
  branch 
  divides 
  again, 
  and 
  passes 
  anteriorly 
  to 
  the 
  head 
  and 
  mouth-parts, 
  a 
  second 
  

   branch 
  passes 
  towards 
  the 
  middle 
  line 
  and 
  joins 
  its 
  fellow 
  from 
  the 
  other 
  side, 
  thus 
  

   forming 
  the 
  mesothoracic 
  transverse 
  tracheal 
  trunk 
  ; 
  a 
  third 
  main 
  branch 
  passes 
  

   posteriorly 
  and 
  unites 
  with 
  an 
  anterior 
  branch 
  from 
  the 
  trunk 
  into 
  which 
  the 
  meta- 
  

   thoracic 
  spiracle 
  leads, 
  thus 
  forming 
  a 
  longitudinal 
  thoracic 
  tracheal 
  trunk. 
  

  

  Each 
  metathoracic 
  spiracle 
  leads 
  into 
  a 
  trunk 
  which 
  divides 
  immediately 
  into 
  four 
  

   main 
  branches. 
  One 
  of 
  these, 
  as 
  we 
  have 
  seen, 
  helps 
  to 
  form 
  the 
  longitudinal 
  trunk 
  

   of 
  the 
  thorax 
  ; 
  a 
  second 
  helps 
  to 
  form, 
  as 
  in 
  the 
  mesothorax, 
  a 
  transverse 
  trunk 
  

   a 
  third 
  and 
  fourth 
  branch 
  pass 
  backwards 
  into 
  the 
  abdomen 
  as 
  a 
  dorsal 
  and 
  ventra 
  

   trunk 
  ; 
  the 
  dorsal 
  abdominal 
  trunks 
  of 
  each 
  side 
  unite 
  posteriorly. 
  

  

  Each 
  spiracle 
  of 
  the 
  abdominal 
  series 
  of 
  seven 
  pairs, 
  leads 
  into 
  a 
  narrow 
  tracheal 
  

   tube, 
  which 
  soon 
  bifurcates, 
  giving 
  rise 
  to 
  a 
  dorsal 
  and 
  a 
  ventral 
  branch, 
  which 
  join 
  

   the 
  dorsal 
  and 
  ventral 
  abdominal 
  trunks 
  respectively. 
  The 
  ventral 
  branches 
  from 
  

   the 
  last 
  three 
  spiracles 
  join 
  the 
  ventral 
  abdominal 
  trunk 
  at 
  the 
  same 
  point. 
  A 
  

   transverse 
  trachea 
  tube 
  connectsthe 
  dorsal 
  branches 
  leading 
  from 
  the 
  last 
  pair 
  of 
  

   abdominal 
  spiracles, 
  just 
  posterior 
  to 
  the 
  anus. 
  

  

  The 
  arrangement 
  of 
  the 
  spiracles 
  is 
  the 
  same 
  in 
  both 
  male 
  and 
  female 
  insects. 
  

  

  * 
  Newstead, 
  "Monograph 
  of 
  British 
  Coccidae," 
  i, 
  1900, 
  p. 
  15. 
  

  

  